| Wild soybean(Glycine soja) could survive in a relative severer sodic soil regions which may illustrate that there may exist two kinds of mechanism to respond to these unfavorable environmental stimuli. Hence, wild soybean is an ideal material to study the physiological mechanism of plants to salt and alkali stress. In recent years, tremendous progress has been made in understanding plant response to external stimuli. However, most researches mainly focused on the salt stress, and very limited progress was found for alkali or saline-alkali mix stress, especially on molecular function.The wild soybean(G07256) used in this study with a strong resistant ability against alkai stress, which can germinate and set seed in the salt-alkaline soil at pH9.02.In order to understanding its response of molecular mechanism to the salt-alkali mix stress, we used50mM NaHCO3solution(pH8.5) to simulate the salinity mixed stress. Through Illumina solexa sequencing technology, we obtained the wild soybean root genes expression profile under NaHCO3stress. This study could helps us to investigate the alkaline resistant genes and better understanding the molecular mechanisms of plants under salt-alkali mixed stress, as well as to provide theoretical basis for genetic resources in plant molecular breeding.The main results and conclusions are as follows:1. Through Illumina Solexa sequencing, we obtained3380differential expressed genes under the NaHCO3stress. We altogether identified1443,1266,1162,1267,1162differential expressed genes from control groups and treatment groups. These genes’ expression quantities peaked at6h under NaHCO3stress while decreased at12h to24h.2. Within6hs under NaHCO3stress, the genes of Glycine soja (G07256) expressed vigorously while between12h to24h, the express of it became slowly, and the number of differential expressed genes decrease sharply. Among them, the number of down-regulated genes were almost the same in different times, while about12h,, the number of it became sharply increased. We suggested that under NaHCO3stress6h is an early response time point, while the12h is the turning point of genetic response.3. We obtained11gene expression patterns under NaHCO3stress; making gene function classification and pathway enrichment analysis, we found that wild soybean root response presented a cascade process.The main pathways and functions were as follows: hormone signal transduction, transcriptional regulation,immune system, carbohydrate metabolism pathways.4. Co-differentially expressed genes function analysis showed that the function of most of the down-regulated genes were associated with histone modification or plant growth process related.5. Realtime-PCR validation showed that the relative expression quantities of12genes are consistent with Illumina solexa sequencing results. This proves that sequencing results is relatively accurate and we could use it in the following study.6. Analysis the alternative splicing of wild soybean under NaHCO3mixed stress, we found that the main alternative splicing type is exon3’alternative, the following is exon deletion. Under NaHCO3stress with3h, the number of these two kinds of alternative splicing type achieved most then dropped until24h. This finding laid a foundation about the research about the salinity-alkalinity stress influence alternative splicing.7. The characteristics of the transcirptome analysis found many novel transcripts which contains so many low expression abundance new transcripts. It means great significance for supplement of wild soybean genome sequence data. In SNP related analysis, we mined1324non-synonymous mutations SNP, which laid a theoretical foundation on wild soybean and cultivated research about their phenotypic traits and differences. |
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